Plunger pump



Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to hollow plunger deep well pumps of that generaltype in which the seal between the plunger and pump barrel isaccomplished by a plurality of stationary tubes 5 and movable tubesnested therewith, which tubes provide a labyrinthine path through whichfluid must travel before it can pass the plunger and by means of whichlabyrinth leakage or slip is reduced.

It further relates to a pump assembly which may be lowered into the welland/or removed therefrom through the discharge pipe, and to the means bywhich the said assembly is sealed to the pipe when so lowered andseated.

Pumps of this general type have been previously known. Ordinarilyhowever, in such pumps the cylinder has consisted of an outer tube orbarrel and an inner tube supported at the bottom of the barrel andextending upward, and a plunger of two tubes, both secured to a plungerhead and extending downward, the inner within and the outer between thetwo tubes of the barrel. Such construction has proved inefiicient inthat the pocket so formed in the upper end of the plunger and thesimilar pocket at the lower end of the barrel, both trap and compressthe fluid being pumped on the downward stroke of the plunger, whichstroke is accomplished solely by gravity, seriously shortening thestroke except at excessively slow speeds, and greatly reducing thecapacity of the pump.

In an attempt to obviate this situation so far as the lower pocket isconcerned, the outer wall of the cylinder has been moved away fromcontact with the outer of the plunger tubes, and that part of thelabyrinth abandoned; and openings have been made through the inner wallof the plunger to relieve the resulting compression and shortening ofstroke caused by the other pocket. To make this latter constructionefiective two valves have been found necessary in the plunger itself.

In such construction also, the plunger forms no support for the cylinderin lowering the pump assembly through the discharge pipe to its seat andadditionally provides no means, per se for removing the cylinder portionof the assembly from the well should such removal be found necessary. Toobviate this difficulty, threaded 1 means or other disengageable typesof coupling means have been found necessary in order to secure the pumpand cylinder together for lowering into the well, such coupling meanshaving to be disengaged in some manner, as by rotation of the plungerbefore pumping is begun. Conversely they have to be re-engaged beforeremoval in case the same becomes necessary. Recoupling particularly isordinarily accomplished only with considerable difliculty and inaddition when accomplished is so close as to allow little if any play,so that a direct pull must be used in breaking loose the seal, ratherthan a jarring one which would be much more advantageous.

The objects of my invention are:

To provide for a plunger pump, a labyrinthine seal in which thecompression pockets formed, are acted on during the mechanicallycontrolled upstroke of the plunger, and therefore cannot alter thelength of stroke.

To provide a labyrinthine seal construction in which positive dischargefrom compression pockets is available to clear sand from thelabyrinthine passages and to assist in preventing leakage therethrough.

To provide a labyrinthine seal, pump construction in which fluid istrapped in two opposed interconnected pockets, the pressure in onepocket substantially balancing that in the other thereof, minimizingflow therebetween and rendering substantially all of the fluid trappedeifective to remove sand and oppose leakage.

To provide a pump construction in which the coacting areas of the movingand stationary tubes increase as the effective plunger strokeprogresses.

To provide a labyrinthine seal, pump-construction in which the plungerassembly supports the cylinder assembly during lowering into or removalof the pump assembly from the well and in which movement of the plungeris available to establish blows against the cylinder assembly to assistin dislodging the seal from its seat.

To provide in a deep well pump a removable pump assembly placeableand/or removable through a discharge pipe which has a supporting seat atits effective lower end, said pump assembly having at its upper endsupporting means adapted to cooperate with said seat, wherebysubstantially all of said assembly depends below said seat and is notsubject to silting up.

The means by which the foregoing and other objects are accomplished andthe manner of their accomplishment will readily be understood from thefollowing description on reference to the accompanying drawing, inwhich,

Fig. 1 is a vertical section of my pump through the discharge pipe andthe pump assembly.

Fig. 2 is a fragmentary section showing a modified form of sealingmeans.

Referring now to the drawing in which the various parts are indicated bynumerals, II? is a discharge pipe, I l a coupling, and I2 a casingsection depending below the coupling II and enclosing the pump. Thecoupling I I is bored out at I3 to loosely fit the exterior of the pumpand is counterbored to form an annular shoulder I I to support thecylinder assembly. I5 is a head for the cylinder assembly. This head isprovided with an outwardly extending annular flange I6 which overliesthe annular shoulder M of the coupling II. I! is a seal, preferably oflead disposed between the shoulder I4 and flange It to support thecylinder assembly and seal the same to the coupling II and dischargepipe. This seal is preferably secured to the cylinder head I5 by tinningthe exterior of the head and casting the lead ring therearound. I V

Depending from the head I5, is an outer tube I8 forming the outer wallor barrel of the cylinder and shorter inner tube I9 spaced therefrom.The barrel I8, at its lower end, supports a valve seat 29. 2| is a ballvalve cooperating with this seat and 22, a pin limiting the travel ofthe ball valve 2 I.

The plunger comprises a head 25, provided with the usual threaded shank26 for attachment to the pump rod (not shown). The head 25 is providedwith the usual annular valve seat 21 and ball valve 28, the upperportion of the head forming a cage for the valve 28 and being providedwith openings 29 through which discharge of pumped fluid is effectedinto the discharge pipe IE3. Secured to and depending from the head 25is a tube 30 lying within the inner cylinder tube and having a workingfit therewith. At its lower end the tube 35 is secured to and carries ahead 3I which is shown as a thickening and enlargement of the tube, butmay be otherwise formed. 32 is a hollow valve seat secured inthe headill. 33 is a ball valve and 34 a pin limiting movement of this valve.Secured to the head 3| and extending upwardly therefrom, is a second andshorter plunger tube 35, spaced outwardly from the tube 35, the surfacesof this tube having a working fit with the interior of the cylinderbarrel I8and the exterior of the cylinder tube Ill. The tubes It and 35are both shorter than their respective related barrel and plunger tubes,leaving pockets 35 and 3'! in the barrel assembly and plunger assemblyrespectively.

When assembled and nested, as shown, the cylinder and plunger tubes forma labyrinth seal surrounding the hollow plunger and valve construction,the provision of four tubes and the resulting two pockets substantiallybalancing the pressures along the contiguous surfaces of the two shortertubes and creating along such surfaces a minimum, if any, leakage flow.

It will be seen that the lower head 3! of the plunger and the tube 35supported thereby underlie the tube I9 and head I5 of the cylinderassembly so that the cylinder'assembly is supported by the plunger andcan be lowered or removed thereby.

It will particularly be noted that the depending cylinder assembly lendsitself to the placingof the seal at the top of the cylinder and inposition where any deposit of sand is minimized by agitation due tomovement of the plunger and discharge therefrom, such packed sandbeingone of the most serious troubles encountered in removal of pump barrels.

In Fig. 2 the pump assembly is supported in the coupling I IA and sealedthereto by a seal comprising seating cups AIL-4| held in place byretaining rings 62, 43 respectively and secured by a retaining nut M.

Operation supports the cylinder assembly, the weight of the assemblycompressing the link I! to seal the cylinder head I5 tothe coupling IIand com- "pleting the installation.

In thus lowering the pump assembly into the well the plunger assemblysupports the cylinder assembly, the lower head SI of the plunger and thetube 35 thereof underlying the inner tube I9 and head I 5 of thecylinder assembly.

To operate the pump, the plunger assembly is lowered and raised in usualmanner by well known apparatus at the top of the well, such as is now ingeneral use. Descent of the plunger is largely accomplished in thisoperation by gravity since the long plunger rod ordinarily used is tooflexible to impart a direct thrust. Raising of the plunger however is bydirect pull of the rod and therefore the upper limit of the plungerstroke is definite. During the down stroke fluid within the cylinderbarrel is trapped by the foot valve 2i and enters the plunger barrelthrough the lower valve 33 thereof. On the up stroke this fluid israised by the plunger and additional fluid drawn into the cylinderthrough the foot valve and the operation continued in usual manner toaccomplish pumping. During this action the barrel 30 and tube 35 of theplunger slide within and against the tube I9 and barrel I8 of thecylinder. On the down stroke fluid is drawn upward between the outerwall of the plunger tube 35 and the inner wall of the cylinder barrel I8into the pocket 36, and similarly fluid is drawn downward along theoutside of the plunger barrel 30 and between such tube and the inside ofthe cylinder tube I9 into the lower pocket 3?. Also flow may occur fromor to the pocket 36, to or from the pocket 31 along the contiguoussurfaces of the cylinder tube I9, and the plunger tube 35, but thepressures in the two pockets are substantially equal and such flow ormovement is not usually material.

On the up stroke fluid within the pockets 36 and 31' is forcedtherefrom, substantially all of this flow from the pocket 36 occurringbetween the inside of the cylinder barrel I8 and the outside of theplunger tube 35, and from the pocket 31 between the inside of thecylinder tube l9 and the outside of the plunger barrel 3!]. If the fluidbeing pumped is a true liquid, such as water with substantially noentrained gases, this flow in both the upper and lowered pockets must bein direct proportion to the area of the pockets and the plunger stroke.If however, the fluid to be pumped is a fluid such as oil containing alarge proportion of entrained gases, the pockets need neither fillcompletely nor empty completely, owing to the compressibility andexpansibility of the entrained gases, and therefore the flow of fluidfrom and to the pockets in such case would be largely reduced from thecorresponding flow where a true liquid is pumped.

In ordinary pumping the fluid is often accompanied by considerablequantities of sand. So far as actual pumping is concerned, sand drawn inthrough the foot valve 2| passes upward into the plunger, is raisedthereby and largely passes with the fluid directly to the surface and isdischarged therewith. There is a tendency however for some of the sandto follow the fluid drawn along the sealing surfaces of the tubes andinto the pockets. In both cases however, the tendency of the sand is tofollow the freer flow of the fluid pumped and a minor quantity only isdrawn along these sealing surfaces toward the pockets. On the up strokethe fluid within the pockets is definitely forced out by the up strokeof the plunger and clears or tends to clear all of this sand from thesesurfaces, the evacuation of fluid from the pockets ofiering a definiteresistance to the plunger stroke. In the present case this resistance isovercome by the definitely fixed movement of the plunger raisingmechanism, and therefore irrespective of the speeds must be fullyaccomplished at each stroke, whereas the evacuation of the pockets werethese pockets inverted would be accomplished only by gravity and even atnormal speeds evacuation of the pockets would not be complete and thecapacity of the pump would be greatly lowered.

After continued use of the pump, it is often found necessary to removethe same for overhauling and/or cleaning, and such removal requiresdislodging the seating seal and also dislodging of any sand which mayhave packed over and around such seal. In the instant device,particularly where oil containing entrained gases has been pumped, it ispossible by slightly lowering the pump rod and thereby separating theends of the tubes l9 and from the bottoms of their respective pockets,to accomplish by sharp upward movement, a blow or jar which is effectiveto dislodge the seal I! from its seat and thereby permit the removal ofthe pump assembly from the well.

It will again be noted, that at all times portions of the plungerassembly underlie portions of the cylinder assembly so that they aredefinitely locked together at all times, making it possible not only touse this jarring stroke to release the seal between the pump assemblyand its support, but also making the plunger assembly inherentlyeffective for the subsequent removal of the cylinder assembly and thusobviating the difliculty often unsurmountable of coupling these partstogether as a condition precedent to the removal of the cylinderassembly.

What I claim is:

1. In a pump having a discharge pipe with an annular seat adjacent itslower end; a cylinder assembly and a plunger assembly reciprocablycooperating, said cylinder assembly comprising an annular head havingannular supporting and sealing means cooperating with said annular seat,

-a barrel and a tube spaced inward therefrom,

both secured to and depending from said head, said tube being shorterthan said barrel, and a foot valve carried by said barrel; said plungerassembly comprising a working valve, an annular upper head, a barrelsecured to and depending from said head within said cylinder tube andhaving a working fit therewith, an annular lower head carried by saidbarrel and a tube shorter than said barrel spaced outward therefromsecured to and extending upward from said lower head, said plunger tubelying between said cylinder barrel and cylinder tube and having aworking fit with said barrel, said cylinder barrel and tube and saidplunger barrel and tube forming together a labyrinthine passagewayinterrupted by upper and lower pockets both decreasing in volume on theupstroke of said plunger and having discharge escape only along therespective working surfaces between said barrels and their cooperatingtubes; whereby leakage downward along the pump barrel due to thepressure of the fluid column during the pumping stroke is opposed byupward discharge flow from the lower pocket augmented bycounterbalancing pressure from the upper pocket.

2. In a pump having a discharge pipe with an annular seat adjacent itslower end; a cylinder assembly and a plunger assembly reciprocablycooperating, said cylinder assembly comprising an annular head havingannular supporting and sealing means cooperating with said annular seat,a barrel and a tube spaced inward therefrom, both secured to anddepending from said head, said tube being shorter than said barrel, anda foot valve carried by said barrel; said plunger assembly comprising anannular upper head carrying a working valve, a barrel secured to anddepending from said head within said cylinder tube and having a workingfit therewith, an annular lower head carried by said barrel and a tubeshorter than said barrel spaced outward therefrom, secured to andextending upward from said lower head, said plunger tube lying betweensaid cylinder barrel and cylinder tube and having a working fit withsaid barrel, said cylinder barrel and tube, and said plunger barrel andtube, forming together a labyrinthine passageway interrupted by upperand lower pockets both decreasing in volume on the upstroke of saidplunger and having discharge escape only along the respective workingsurfaces between said barrels and the cooperating tubes; whereby leakagedownward along the pump barrel due to the pressure of the fluid columnduring the pumping stroke is opposed by upward discharge flow from thelower pocket augmented by counterbalancing pressure from the upperpocket.

CLIFFORD M. PETERS.

